Gear rolling machine

ABSTRACT

Machine for rolling a gear with a gear-like die which includes means for measuring and/or controlling the final separation between the axes of the gear and die so as to produce uniform size finish-rolled gears.

United States Patent 1 1 I 1111 3,712,094

Motz et al. [4 1 Jan. 23, 1973 [54] GEAR ROLLING MACHINE 3,552,167 11971 Bergi et al. ..72/108 x [75] Inventors: Carl Mm, Russell Anthony,3,533,258 10 1970 Leonard, Jr. et al. ..72/108 both of Harper Woods Mich2,423,932 7/1947 Fmzel ..72/102 2,726,541 12/1955 Sims ...73/88.5

Assign: Lear Siegler, Inc Santa Monica 3,389,588 6/1968 Remhardtetal..72/8

Calif.

[22] Filed: Feb. 4, 1971 [21] Appl. No.1 112,706

Primary ExaminerMilton S. Mehr Att0rney-Whittemore, Hulbert & Belknap[57] ABSTRACT [52] U.S. Cl. ..72/21, 72/94, 72/102 Machine for rolling agear with a gear-like die which [51] Int. Cl. ..B2lh 5/02 in ludes meanfor meas ring n /0r controlling the [58] Field of Search ..72/102, 108,35, 34, 32, 31, final separation between the axes of the gear and die72/104, 21, 25, 94, 22; 29/1592 so as to produce uniform sizefinish-rolled gears.

[56] References Cited 8 c1 9 D F UNITED STATES PATENTS l,240,9l9 9/l9l7Anderson ..72/l02 PATENTEDJAN23I973 3.712.094

SHEET 1 [1F 2 GEAR ROLLING MACHINE BRIEF SUMMARY OF THE INVENTION Ingear rolling a partially formed gear is finish-rolled by rolling it inmesh with one or more gear-like dies under conditions which establishrelatively great pressure between the teeth of the gear and die or dies.Where this operation is carried out by engaging a gear with a singledie, it has been found that small variations in size of a series of workgears prior to rolling are not completely eliminated. This is in manycases at least partly because of distortion of the frame of the machineunder the relatively massive loads imposed in gear rolling.

In accordance with the present invention means are applied directlybetween the gear support and the die support to control the finalseparation between the axes of the gear and tool.

In a simple case, this means may simply be constituted by a rigidabutment. In other cases it may take the form of highly accuratemeasuring means and may include means for developing a signal which willterminate the application of rolling pressure, either abruptly or undera predetermined program including initial dwell and subsequent reductionin pressure.

Another alternativeis to provide a rigid abutment associated withpressure sensing means so that forces continue to be applied until thework gear is sufficiently reduced to permit the abutment to assume apredetermined loading.

The invention is applicable not only to single die rolling, but alsotosituations in which a pair of opposed dies are provided.

BRIEF DESCRIPTION OF THE DRAWINGS tion, showing the invention applied toopposed rolls.

FIGS. 8 and 9show fragmentary elevational views partly in section, ofmodifications of the machine shown in FIG. 7.

DETAILED DESCRIPTION Referring first toF-IG. I there is illustrated agear rolling machine comprising a frame 10 having a forwardly extendingbase 12, avertical column 14, and a forwardly extending top portion 16,the whole constituting whatmay be aptly described as a C-frame. Mountedfor-vertical movement at the front side of the column 14 by ways 18,there is provided a knee having stocks 22 thereon which support a workgear W for rotation..Secured to the underside of the forwardlyprojecting top frame portion I6isa die support 24 which isillustrated'as connected to the top portion 16 for angularadjustment'about a vertical axis by suitable means such as a pilotingdisc 26.

A shaft .28 is journaled in the support 24 and carries a gear-likerolling die D. Means diagrammatically indicated asa motor drive 30 'isprovided for driving the die in rotation.

The knee 20 is connected to power mechanism diagrammatically indicatedas a'piston and cylinder device 32 for effecting vertical movement ofthe knee and for applying rolling forces between the teeth of the die Dand the work gear W.

It will be appreciated that the forces acting directly between the die Dand the gear W tend to distort the C- shaped frame 10 of the machine.While the frame is massive and substantially rigid, nevertheless underthe relatively great forces imposed, deflections of a few thousandths ortens of thousandths of an inch occur.

As a result, if a series of work gears differ in pitch diameter bycorresponding small amounts are rolled in the machine, it has been foundthat while the work gears are reduced in pitch diameter and have thesurfaces of the teeth improved by the rolling action, nevertheless thedifference in sizes of the work gears is not completely eliminated. Inother words, the finished gears continue to show some divergence inpitch diameter.

In accordance with the present invention this divergence infinish-rolled diameter of a series of work gears is substantiallycompletely eliminated by providing an abutment block 34' in position toact substantially directly between the work support for the gear W andthe tool support for the die D. Specifically, the block 34 is shown asengaging between the top of one of the stocks 22 and the underside ofthe die support 24. It will of course be appreciated that if considerednecessary a second identical abutment may be interposed between the diesupport 24 and the other work supporting stock 22.

It will be apparent that forces applied by the device 32 will continueto move the knee 20 upwardly, irrespective of any deflection or bendingwhich may take place in the frame 10 until the axes of the work gear anddie reach a predetermined spacing as determined by the block or abutment34. Accordingly, with this arrangement a series of work gears whichdiffer by small amounts in pitch diameter prior to the gear rollingoperation, will all have identical or substantially identical pitchdiameters after the rolling operation has been completed.

. In carrying out the gear rolling operation it is only necessary toinsure that the abutment 34 is solidly engaged to limit furtherupward'movement of the knee 20 and that the parts remain in thisposition until the gear has made at least a complete revolution andpreferably a number of revolutions.

It will of course be appreciated that the rolling operation of the gearinvolves plastic deformation of material of the teeth as well as elasticdeformation. Accordingly, the dimensions of the abutment 34 will be suchas to take into account the elastic deformation so that upon removalfrom the machine, the finish-rolled gear in unstressed condition willhave the required pitch diameter.

In the foregoing description the block 34 has been described as a simpleabutment. It may however, take the form illustrated in FIG. 2 where ablock 40 is provided with an adjustableabutment screw 42.

A further embodiment of the invention is illustrated in FIG. 2 where, ifdesired, means are provided in association with the block 40 (or theblock 34 as illustrated in FIG. 1) responsive to pressure. Such meansmay for example take the form of a strain gauge, transducer, or otherpressure responsive means as illustrated at 44 having electricalconnections 46 leading to suitable control mechanism for controlling thedevice for feeding the knee upwardly. This may of course take the formof solenoid controlled valves for controlling the application of fluidunder pressure to the cylinder of the piston and cylinder device 32.

As the knee is moved upwardly relatively massive forces are developedbetween the die and gear, causing plastic deformation of the material ofthe gear teeth. As this deformation of the gear teeth continues, withaccompanied reduction in size of the pitch diameter of the gear,eventually the abutment 40 will be solidly engaged between the work anddie support. The initial engagement will take place with minimum force,and the maximum force applied by the actuating device 32 will continueto be applied. As further plastic and elastic deformation of the gearteeth takes place, the division of total force applied by the piston andcylinder device 32 changes and eventually, the force applied to the gearis only that required to produce elastic deformation thereof. Theapplication of increased force by the piston and cylinder device 32 willhave no effect on the gear but will merely apply greater force to theabutment 40.

With this arrangement the pressure sensitive means 44 may be selected oradjusted so as to terminate or gradually reduce the application oflifting force to the knee when a predetermined force has been applied tothe abutment.

Referring now to FIG. 3 there is illustrated an arrangement in which theseparation between the axes of the die D and the work gear W is measuredby a sensitive indicator 50 which may be in the form of a dial indicatorhaving an indicating needle 52 and a plunger 54 engageable with theunderside of the die support 56. The indicator 50 rests on the knee 20.In its simplest form the operator may merely observe the needle 52 anddiscontinue application of force to the knee 20 when the indicator showsthat the axes of the gear and die have reached the required minimumseparation. Preferably however, the indicator includes contactsconnected to conductors 58 which operate upon a predetermined reading ofthe indicator to effect automatic control of the application of force tothe knee 20.

The means for automatically terminating the gear rolling operation whenthe work gear has been reduced to a required dimension may of courseoperate to effect abrupt termination of the application of upwardlydirected force to the knee and permit or provide for downward movementof the knee to a clearance position. However, it is normally desirableto use the signal established when the axes between the die and gearreach a predetermined spacing to initiate a termination program whichmay include continued operation for a predetermined brief interval,followed either by an abrupt separation or a first gradual separationbetween the gear and die and then by an abrupt separation to unloadingand loading position.

Referring now to FIG. 4 there is illustrated a modified arrangement inwhich the die support 60 carries a die here designated 62, which ismounted on a spindle 64. The spindle 64 carries a pitch abutment disc66. The knee of the machine is illustrated at 68 and ineludes stocks 70carrying a spindle 72 on which the work gear W is mounted. The shaft 72carries a pitch abutment disc 74 which is adapted to engage directlywith the pitch abutment disc 66 when the axes of the gear and die havereached the predetermined desired final position.

The discs 66 and 74 are referred to as pitch abutment discs because theyhave diameters respectively equal to the pitch diameters of the gear anddie. Accordingly, when the gear has been reduced to its requireddimension, the pitch abutment discs constitute abutment means preventingfurther infeed and at the same time, the continued rolling operationtakes place without appreciable slippage between the pitch abutmentdiscs.

Referring now to FIG. 5 there is illustrated a further embodiment of theinvention. In this case an indicator 80, having contacts or switch meansconnected to external conductors 82, is carried by a sleeve 84 which isvertically adjustable on a rod 86 by fine adjustment means (not shown)and including a clamp 88 to lock the indicator in adjusted position. Therod 86 extends through a bracket 90 fixed to the tool support 24 and acoarse adjustment is provided by moving the rod 86 through the bracket90 and fixing it in adjusted position by a clamping screw 92. Theindicator of course is provided with a plunger 94 which engages the knee20.

This device operates exactly in the same manner as the arrangementillustrated in FIG. 3, but provides a coarse adjustment operable whenchanging over from differently dimensioned parts.

Referring now to FIG. 6 there is illustrated an arrangement in which thetool support, here designated 100, carries a pneumatic gauge 102 havinga downwardly extending proximity portion 104 adapted to approach theupper surface 106 of the knee, here designated 108. Air under pressureis supplied to the gauge through a conduit 110 and the relative positionbetween the knee 108 and the tool support 100 determines the pressurewithin the gauge, which is used to provide a reading on a dial 112. Atthe same time, the pressure variation may be used to control theapplication of upward forces to the knee.

Referring now to FIG. 7 there is illustrated an arrangement in which thework gear W is rolled between a pair of opposed dies D1 and D2. TheC-shaped frame is diagrammatically indicated at and the knee 122 ismovable upwardly by power means diagrammatically indicated as the pistonand cylinder device 124. It will be appreciated that the illustratedconstruction mounts the upper die D1 in a fixed position and thatrolling forces are applied to the work gear W by upward movement of thelower die D2 and by appropriate upward movement of the work gear W tomaintain it centralized between the upper and lower dies. The dies DIand D2 are driven in timed relation by gearing including gears I26 and128 which are appropriately geared together to provide for accuratelytimed rotation.

In accordance with this embodiment of the invention an abutment 130 ispositioned between stocks 132 and 134 supporting the upper and lowerdies. Accordingly, upward movement of the lower die is continued untilsuch movement is arrested by the abutment 130, at which time the axesbetween the upper and lower dies are spaced apart a predetermineddistance independent of any deflection which may have occurred in the C-frame 120.

As previously suggested, the block or abutment 130 may be provided withpressure sensitive means such for example as a strain gaugediagrammatically illustrated at 136 which may be employed to transmit asignal to control the application of pressure to the piston and cylinderdevice 120.

Referring now to FIG. 8 there is illustrated an embodiment of theinvention similar to that illustrated in FIG. 7 except that instead ofemploying a rigid abutment interposed between the die and gear supports,there is provided a gauge 140 having a plunger 141 adapted to engage arigid element 142 on the support for the upper die D1. The gauge 140 ismounted on rigid support structure 144 carried by and movable with theknee 146. Again, the gauge or indicator 140 is provided with circuitcontrolling means and external conductors 148 leading to controls forthe feed device 124 (FIG. 7).

FIG. 9 diagrammatically illustrates the application of pitch abutmentdiscs 150 to the dies D1 and D2 associated with a pitch abutment disc150 mounted on the arbor 154 which supports the work gear W. It will beappreciated that as the knee, here designated 156, moves upwardly thespacing between the axes of the dies D1 and D2 decreases until the pitchabutment discs engage, thus limiting further upward movement of the knee156 and further reduction in size of the work gear W.

In any of the foregoing systems the control means which controls thecontinued application of force producing relative infeed of the die ordies relative to the gear, may be actuated by means sensing the positionof the die or dies relative to the gear, or it may be actuated byattainment of a predetermined pressure by rigid abutment means. Theprograms initiated by the controls may of course include simple reversalof die movement or it may include a predetermined dwell followed byabrupt or gradual outward movement of the die.

The invention is applied to a gear rolling machine in which the frame ofthe machine is generally C-shaped. The column 14 constitutes anintermediate portion of the frame and the parts 12 and 16 constitutelimbs extending laterally from the intermediate portion in the samedirection. By the present invention the deflection of the frame whichinherently occurs as a result of the relatively great forces applied inthe gear rolling operation, is not permitted to affect the dimensionalaccuracy of the finished part since this is determined by meanscontrolling the actual separation between the axis of the gear and theaxis or axes of the rolling tool or tools employed.

In the simplest operation embodying the present invention, rigidabutment means are provided to limit the approach between the axes ofthe work gear and the die or dies, and feeding pressure is applied for asufficient interval to assure that the amount of infeed is sufficient tobring about engagement of the abutment means and preferably to continuerotation of the gear and die or dies for a brief predetermined interval.Thereafter, the die or dies and work gear are separated, either with aninitial gradual separation followed by abrupt separation to loading andunloading position, or by abrupt separation to such position.

The rolling of gears may be divided into rolling from the solid, inwhich case the work piece starts out as a cylindrical blank; orfinish-rolling, m which case the work piece has been rough machinedeither by cutting, rolling, or otherwise prior to the finishingoperation. The present invention basically controls the final size ofthe finish-rolled gear and hence, is most applicable to a finish rollingoperation. However, it is applicable in many cases to rolling from thesolid, particularly where conditions are such that no subsequent finishrolling operation is to be performed.

What we claim as our invention is:

1. A gear rolling machine comprising a generally C- shaped frame havingan elongated intermediate portion, and limbs extending laterally in thesame direction from said intermediate portion, a slide movablelongitudinally on said intermediate portion, rotary supports on one ofsaid limbs and said slide for a rotary gear-like die and a rotary workpiece to have teeth thereon rolled in pressure contact with teeth on thedie, drive means for driving one of said supports in rotation, feedmeans connected between said slide and said other limb for moving saidslide to move one of said rotary supports generally radially of theother to cause plastic deformation of metal of the teeth of the workpiece, and control means responsive substantially directly toactualspacing between the axes of said die and work piece to control movementof said slide to provide for accurate sizing of the work pieceindependent of any deformation of said frame.

2. A machine as defined in claim 1 in which said control means comprisesa rigid abutment acting substantially directly between said supports tolimit feed movement of said slide.

3. A machine as defined in claim 1 comprising an abutment actingsubstantially directly between said supports, and means responsive tothe pressure applied to said abutment to control operation of said feedmeans.

4. A machine as defined in claim 1 in which said control means comprisesmeasuring means for measuring the spacing between the axes of saidrotary supports.

5. A machine as defined in claim 4, and means responsive to apredetermined spacing between the axes of said rotary supports tocontrol said feed means.

6. A machine as defined in claim 1 in which a single die is employedwith a gear.

7. A machine as defined in claim 1 in which a pair of dies are employedat opposite sides of a gear and in which the control means is directlyresponsive to spacing between the dies, the work piece being centeredbetween the dies.

8. A machine as defined in claim 1 in which the rotary work piece is inthe form of a gear having teeth provided with a small amount of excessmaterial to be distributed by plastic deformation to reduce the pitchdiameter of the gear to a required dimension.

1. A gear rolling machine comprising a generally C-shaped frame havingan elongated intermediate portion, and limbs extending laterally in thesame direction from said intermediate portion, a slide movablelongitudinally on said intermediate portion, rotary supports on one ofsaid limbs and said slide for a rotary gearlike die and a rotary workpiece to have teeth thereon rolled in pressure contact with teeth on thedie, drive means for driving one of said supports in rotation, feedmeans connected between said slide and said other limb for moving saidslide to move one of said rotary supports generally radially of theother to cause plastic deformation of metal of the teeth of the workpiece, and control means responsive substantially directly to actualspacing between the axes of said die and work piece to control movementof said slide to provide for accurate sizing of the work pieceindependent of any deformation of said frame.
 2. A machine as defined inclaim 1 in which said control means comprises a rigid abutment actingsubstantially directly between said supports to limit feed movement ofsaid slide.
 3. A machine as defined in claim 1 comprising an abutmentacting substantially directly between said supports, and meansresponsive to the pressure applied to said abutment to control operationof said feed means.
 4. A machine as defined in claim 1 in which saidcontrol means comprises measuring means for measuring the spacingbetween the axes of said rotary supports.
 5. A machine as defined inclaim 4, and means responsive to a predetermined spacing between theaxes of said rotary supports to control said feed means.
 6. A machine asdefined in claim 1 in which a single die is employed with a gear.
 7. Amachine as defined in claim 1 in which a pair of dies are employed atopposite sides of a gear and in which the control means is directlyresponsive to spacing between the dies, the work piece being centeredbetween the dies.
 8. A machine as defined in claim 1 in which the rotarywork piece is in the form of a gear having teeth provided with a smallamount of excess material to be distributed by plastic deformation toreduce the pitch diameter of the gear to a required diMension.